Weather & Seasons
Monthly climate breakdown, seasonal tips, and advice on when to go — from peak dry season to the quietest wet months.
Verified 2026 · Island Seeker Editorial
quick answer
The best time to visit Koh Lanta is November to April — the dry season. December to February sees the most reliable sunshine and calmest seas. March and April are warm but still very pleasant. May marks the start of the wet season; June through October can bring heavy rain and rough seas, and many businesses on the island close entirely. November is the sweet spot: drier conditions return, crowds haven't peaked, and prices are lower than December.
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Best months
November – April
Wet season
May – October
Average temp
28–34°C year-round
Peak season
December – February
November to April is Koh Lanta's dry season, with minimal rainfall, sunny skies, and calm seas — ideal for swimming, snorkelling, and diving. December through February is the peak of the season: days are warm (28–30°C), evenings are pleasant, and the Andaman Sea is flat enough for long-tail boat trips to nearby islands and dive sites. This is also the busiest and most expensive period — book accommodation weeks in advance during Christmas and New Year.
March and April bring slightly hotter temperatures (32–35°C) with minimal rain, though seas can develop a mild swell by April as the monsoon approaches. Many Europeans who escape winter travel in March–April, making it a lively period with good weather. April is Songkran (Thai New Year water festival) — celebrated enthusiastically across Thailand, including Saladan town.
November is consistently cited as one of the best months to visit: the rains have mostly stopped, the island is still quiet from off-season, prices are pre-peak, and the sea is usually calm enough for snorkelling.
The southwest monsoon brings heavy, sustained rain to Koh Lanta from May through October. Seas become rough and ferry services to offshore islands are often suspended. June through September are typically the wettest months — days of continuous rain are common. Most dive operators and boat tour companies suspend operations. Many guesthouses, restaurants, and shops on the island close entirely, particularly from June to September.
October and November represent the transition back to dry conditions. Late October can still be rainy but is usually manageable. By mid-November, the island is largely back to normal operations. Visiting in May or early June can offer lower prices and a quieter experience, but you should have flexible plans and accept that some activities won't be available.
Diving conditions around Koh Lanta are best November to April. The Mu Ko Lanta Marine Park and nearby dive sites (Koh Ha, Koh Bida Nok, Hin Daeng, Hin Muang) have visibility of 15–30m in the dry season. Whale sharks frequent the deeper sites from January to March. The Andaman's dive season aligns tightly with Koh Lanta's dry season.
In the wet season (May–October), most dive shops close. A few operators run sheltered dive trips in May and June during windows of calm weather, but conditions are unpredictable. If diving is a priority, plan for November–April.
questions & answers
Is Koh Lanta open in May?
Most businesses operate through May, though some begin closing toward end-of-month. May is a shoulder month — you'll find lower prices, fewer tourists, and workable weather (intermittent rain, mostly in the evenings). June–September sees widespread closures, so May is the last practical month to visit.
What is the weather like in Koh Lanta in December?
December is peak season: consistently sunny skies, temperatures around 28–30°C, calm seas, and excellent visibility for snorkelling and diving. It's also the busiest and most expensive month — book accommodation early and expect higher prices everywhere. The Christmas–New Year period is especially busy.
Does it rain in Koh Lanta in November?
Early November can see residual rain from the tail end of the wet season, but conditions typically improve markedly by mid-November. By late November, the island usually has full dry-season weather: sunny days, calm seas, and comfortable temperatures. November is considered one of the best months to visit — good weather combined with pre-peak pricing.
How hot is Koh Lanta in April?
April is one of the hottest months on Koh Lanta, with daytime temperatures reaching 33–36°C. There's still very little rain, making it good for beach days, but the heat can be intense in the middle of the day. Sea water temperature is warm (~30°C), which makes swimming comfortable. April is Songkran season — the Thai New Year water festival — celebrated with enthusiasm.
Is Koh Lanta good in February?
February is considered one of the best months to visit Koh Lanta — reliable sunshine, temperatures of 27–30°C, calm seas perfect for snorkelling and diving, and the peak of tourist season which means all restaurants and activities are operating. It's busy and relatively expensive compared to shoulder months, but the weather makes it easy to recommend.
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